The invention relates to material handlers, and more particularly to material handlers with telescoping booms.
Material handlers are vehicles that include telescoping booms which are used to lift and transport loads. A typical telescoping boom includes a rearward end that is coupled to a back end of the material handler and a forward end that extends toward a front end of the material handler. The telescoping boom is extendable between a retracted position where the forward end of the boom is approximately located adjacent to the front end of the material handler and an extended position where the forward end of the telescoping boom is extended away from the front end of the material handler. The telescoping boom is also pivotable with respect to material handler between a lowered position where the telescoping boom is substantially horizontal and adjacent to the material handler, and a raised position where the telescoping boom is angled upward from the back end of the material handler such that the forward end of the telescoping boom is raised above the material handler. The telescoping boom is typically equipped with a fork that is insertable underneath a load in order to raise the load and move it to another position.
The load is moved relative to the material handler and therefore it is possible to locate the load into a position that will cause the material handler to become unbalanced and, in extreme circumstances, cause the material handler to roll over. In order to prevent these unsafe conditions, operators of material handlers have historically referred to printed load charts. A typical load chart is illustrated in FIG. 1 and graphically displays safe combinations of extension distances and elevation angles for different load weights. For example, when the material handler is in a static condition, the operator can determine how far the telescoping boom can be safely extended by referencing the elevation angle of the boom and load weight on the chart. Some systems display the distance that the load is extended so that the operator can more accurately determine the other variables from the chart and other systems include warning signals that inform the operator when an unsafe condition exists.
The electronic load chart of the present invention enhances forward stability by identifying when a material handler is operating at a stable loading condition and by accurately indicating when the material handler is operating close to an unstable loading condition based on a distance that a telescoping boom is extended and an angle that the boom is raised. The electronic load chart also increases the overall efficiency of an operator and the material handler by eliminating the need for the operator to flip through manual load charts to determine the safety of a loading condition and by providing the operator with a display that is based on automatically sensed parameters such as boom extension distance and boom angle.
The present invention is directed to a material handler that includes a frame, a telescoping boom, a boom extension sensor, a boom angle sensor, and a control system. The telescoping boom is coupled to the frame, pivotable between a lowered and a raised position, and movable between a retracted and an extended position. The boom extension sensor generates a first signal that corresponds to the distance which the boom is extended. The boom angle sensor generates a second signal that corresponds to the angle which the boom is pivoted. The control system receives the signals and displays a cursor located at a position that is based on the first signal and the second signal.
The present invention is also directed to a method of displaying a load relative to a material handler including providing a telescoping boom that is coupled to a frame. The telescoping boom is movable between a retracted and an extended position and pivotable between a lowered and a raised position. The method further includes sensing the distance that the telescoping boom is extended, generating a first signal based on the sensed distance, sensing the angle that the telescoping boom is pivoted, generating a second signal based on the sensed angle, and displaying a cursor at a position based on the first signal and the second signal.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.